<!DOCTYPE html>
<html>
    <svg viewBox="0 0 10 10">
        <defs>
            <linearGradient id="myGradient">
                <stop offset="0" stop-color="#FF0000" />
                <stop offset="100%" stop-color="#00FF00" />
            </linearGradient>
        </defs>
        <circle cx="5" cy="5" r="4" fill="url('#myGradient')" />
    </svg>
</html>
